Question

A ray from a fixed object is incident of a plane mirror at an angle of 20°.If the mirror is rotated through 30°,by how many degree will the reflected ray be​

Answer 1

After rotating a plane mirror by 30 degrees, the reflected ray changes direction by 60 degrees due to the Law of Reflection.

Step-by-step explanation:

When a light ray reflects off a plane mirror, the angle of reflection is equal to the angle of incidence according to the Law of Reflection. If a mirror is rotated by an angle, the reflected ray will change direction by twice that angle. Therefore, if the mirror is rotated through 30°, the reflected ray will change direction by 60°.

The Law of Reflection governs the behavior of light when it encounters a plane mirror, establishing a relationship between the incident and reflected rays. According to this law, the angle of reflection is equal to the angle of incidence, creating a predictable symmetry in the reflection process. Consequently, if a mirror undergoes rotation, altering its orientation, the reflected ray adjusts accordingly.

Answer 2

the reflected ray will rotate through 60 degrees

Step-by-step explanation:

It all depends on the axis about which the mirror rotates and also the direction about the axis of rotation (clockwise or anticlockwise). If the axis of rotation is orthogonal to the plane of the mirror is zero the reflected ray will not rotate. If the axis of rotation is within the mirror plane and orthogonal to the projection of the incident ray onto the mirror plane the reflected ray will rotate through 60 degrees.